1. Field of the Invention
This invention relates to an improved apparatus for recording and/or reproducing signals as longitudinal tracks which are formed on a recording medium, and more particularly to an apparatus for recording and/or reproducing signals as longitudinal tracks which are formed on a recording medium utilizing a rotary drum system incorporating rotary heads.
2. Description of the Prior Art
In the helical scan type video cassette recorder (VCR) of the prior art, the plane of movement of the recording tape and the plane of rotation of the rotating head are not parallel This is necessary in order to accomplish helical scanning whereby tracks are written on a recording tape on a bias To accomplish this helical scanning, a rotary head drum assembly containing the rotating recording heads is obliquely mounted on the chassis of a VCR Tape is then withdrawn from a cassette by a loading mechanism and is wrapped, obliquely, around the rotary drum Because of the nature of this tape wrapping operation, the tape is subject to stresses not only in its running direction, but also tension imposed on the tape at an oblique angle by the movement of the head drum assembly. To minimize this oblique tension, the head assembly and loading mechanism must be carefully manufactured using precisely machined parts, thereby increasing the cost of the completed unit. In addition, in such a helical scan system, highly accurate tape guides are necessary to insure proper coupling between the tape and the head drum. These helical loading systems are complex and thus result in high manufacturing costs, as well as decreased tape loading times.
To overcome these problems, longitudinal recording systems utilizing a rotary drum have been proposed. One such system is described in U.S. Pat. No. 4,040,109, issued on Aug. 2, 1977 to Kryltsov. Another such example is U.S. Pat. No. 4,819,099 which is assigned to the same assignee as the instant invention.
As shown in the Kryltsov drawings, a rotary drum assembly contains a slot through which magnetic heads are exposed. These magnetic heads travel upward and downward, thereby contacting the full width of the recording tape. However, as shown in Kryltsov, the slot provided in the rotary drum assembly allows an excessively large air gap to form between the heads and the tape. If this gap between the heads and the tape becomes too large and/or fluctuates, the signal recorded on the tape will not be satisfactory for either recording or playback functions.